1. Field of the Invention
The present invention relates to a method for separating leucine from a mixture of amino acids in which both leucine and isoleucine are obtained.
2. Description of the Related Art
Known methods for separating leucine from isoleucine or vice versa include a method in which isoleucine is purified by using methyl ethyl ketone (see Japanese Patent Application (Laid Open) No. 51,440/81), a method wherein a copper or nickel salt is employed (see Japanese Patent Application No. (Laid Open) No. 123,622/75), and a method in which salts of benzenesulfonic acid are utilized (see Japanese Patent Application (Laid Open) No. 149,222/76). In these methods, however, the removal or recovery of solvents or metal salts used is troublesome and costly.
In view of the problems associated with the prior art methods, there has been a need for a new method which makes it possible to separate leucine or isoleucine from a mixture of amino acids containing both leucine and isoleucine, in a convenient manner at a low cost.
The present inventors have conducted intensive investigations with the aim of developing a convenient process for separating leucine from isoleucine or vise versa and, as a result, completed the present invention.